JOHANNESBURG
— SOUTH Africa's largest and oldest political group representing blacks, the African National Congress (ANC), is expected to win a landslide victory in the country's first all-race election in April, which is regarded by most black South Africans as the day of liberation.

The April 27 ballot will mark the end of more than four decades of institutionalized racial segregation known as apartheid, and will extend the vote to the black majority for the first time in the country's 342-year history.

What makes the election unique is the complexity of the transition, which includes a detailed set of preelectoral rules, the first all-race ballot, a five-year period of coalition rule, and a Constitutional Assembly to finalize a draft constitution adopted last November.

It may be unprecedented for the leader of a racial minority to negotiate himself and the ruling party out of power and yet retain enough support from his constituency to serve as deputy to the man his government jailed for 27 years.

``Whether you call this `incremental conversion' or a managed loss-of-control, it is one of the more extraordinary phenomena of contemporary political history,'' a Western diplomat says.

A painstaking process of negotiation has secured the support of at least 80 percent of the population for the transition to democracy, but last-minute negotiations have yet to secure the support of dissenting Zulus and Afrikaners.

The main threat to the election is the prospect of deliberate attempts by spoilers - particularly those loyal to far right-wing leaders and Chief Mangosuthu Buthelezi of the Zulu-based Inkatha Freedom Party (IFP) - to disrupt the poll with political violence.

For black South Africans, the ballot symbolizes not only political empowerment but the promise of socioeconomic empowerment, even though the economy will continue to be dominated by whites for the foreseeable future.

For whites, the election presents the possibility of legitimizing a carefully constructed transition to democracy and reducing levels of violence and political instability to the point where foreign and local investors will commit new funds to the country.

The transitional package includes a complex web of structures to oversee the run-up to the election and a draft constitution that provides for a multiparty parliamentary democracy, an independent judiciary, a bill of rights, and a constitutional court.

Big-party shake-ups

Up to 22 million voters will go to the polls in an election based for the first time on national and regional lists under a system of proportional representation. Under the previous system, voters selected candidates in local voting districts.

The drawing up of party lists for 200 regional and 200 national seats in the National Assembly, which is nearing completion, has forced internal elections and intense jockeying for position. In the case of the ANC alliance with its diverse components, this has been divisive and problematic.

Only parties - and not voters - must register for the election. Voters will present identity documents at the polls. Some 1 million or so identity documents have still to be issued.

The ballot is the culmination of a process sparked by the decision of President Frederik de Klerk in February 1990 to legalize dissent against apartheid and negotiate a transition to democracy with representative leaders of the country's black majority.

Black expectations unleashed by the release of ANC leader Nelson Mandela on Feb. 11, 1990, have been repeatedly frustrated as political violence has spiraled and deprivation in black urban ghettos has deteriorated.

More than 12,000 people, the overwhelming majority of them black, have died in political violence since February 1990, and spiraling crime and disclosures of widespread corruption by the apartheid regime have led to further frustration.

New names, more choice

An estimated 14 million black voters, including Mr. Mandela, will be voting for the first time in their lives.

In addition, some 3 million white voters, 1.8 million mixed-race ``coloured'' voters, and 650,000 Asians will vote for about 20 political parties expected to contest the election.

The ruling National Party (NP), white right-wing parties gathered under the Afrikaner Volksfront, and the Zulu-based IFP are seen as likely to achieve the 5 percent minimum of the national vote that will secure representation in the Transitional Government of National Unity - a five-year period of enforced coalition rule.

Two recent opinion polls have named the ANC as the projected overall winner, with between 64 and 67 percent of the vote.

The NP achieved between 15.8 and 17 percent, the IFP between 5 and 6 percent, the right-wing parties between 3.9 and 7 percent, and the liberal Democratic Party and the militant Pan Africanist Congress each receiving 2 percent.

The question in the mind of voters is not who will win the election but whether the ANC will win the two-thirds majority needed to draw up the constitution on its own.

Election watchdog

Once the election is proclaimed, the success of the country's transition to democracy will depend largely on the Independent Electoral Commission, which is responsible for leveling the playing fields in the run-up to the election and determining whether the ballot is free and fair.

The Commission will have the power to order a crackdown on disruptive elements and will oversee the massive task of educating voters in a country where some 70 percent of the population have never voted before.

The Commission, which includes five international representatives, will be assisted in its task of monitoring the elections by an estimated 5,000 international observers - including some 2,800 of which will be operating under United Nations auspices. The UN component will include 1,800 civilian observers.